[20.03] Millimeter wavelength data of Saturn as a probe of the thermal emission of the rings.

In the past eight years we have examined the microwave
emissions of Saturn's rings and atmosphere at wavelengths
ranging from 0.7 to 21-cm. At these wavelengths, the primary
contribution of flux from the rings is scattered Saturnian
thermal emission. However, at shorter (mm) wavelengths, a
significant contribution from the ring's own thermal
emission should begin to emerge.

To examine this feature, we present high quality data from
the Berkeley-Illinois-Maryland Association (BIMA) and Owens
Valley Radio Observatory (OVRO) arrays. We observed at
wavelengths of 1.3 and 3.0-mm in October 2002 and March
2003, respectively. At that time Saturn's rings were near
their maximum ring opening angle (|B| ~26.5 deg),
projecting the largest ring area possible, allowing us to
adequately map the brightness temperature of the rings even
with the moderate resolution achieved (~3.0'').

As with previous observations, we use our radiative transfer
code (Dunn et al., Icarus 160, 132--160 [2002]) to model the
relative contributions of the scattered and thermal
radiation emanating from the rings and compare the results
to that seen in the data. However, unlike the previous
(centimetric) observations, the present (millimetric) data
serves as an adequate test of the model's ability to account
for the thermal contribution of the rings.

This work was supported in part by NASA grant NAG5-13349 and
NSF grant AST-9981308.